twining



June M; 1929.

R. H. TWINING PROCESS OF AND APARATUS FOR DISTI'LLING WOOD Filed Dec. 1,2, 1924v Rai L5g i 72g VIM s.

the apparatus whereby Patented J une 11, '1929.

.UNITED STATES RALPHv H. TWINING, 0F' MARQUETTE, IVIICHIGAN, AssIGNoR 'To THE PATENT- OFFICE'.

cLEvELANn- CLIFFS IRON COMPANY, 0F CLEVELAND, OHIO, A CORPORATION OF OHIO.

PROCESS OF AND APPARATUS FOR DISTILLING WOOD.

Application filed December 12, 1,924.- Seral No. 755,365.

The drawing illustrates in elevation, but more or less diagrammatically, theparts of my improved process may be carriedout. f

' In the .process of` wood distillation as commonly practiced,`it is customaryto sub-1 jcctthe vapors fronrthe carbonizing retortv after condensation, to repeated distillation for rectification in order to separate out the tar,` after which the distilled-. pyroligneous acid wis used for forming .acetic acid or mixed with lime to form acetate of lime.`

' -In the distillation of wood,- thas heretofore been proposed toexpose the vaporsfrom the carbonizing retort tothe scrubbingaction of tar oil in order-to aid in separating out the `tar from the pyroligneous acid'. Serious objections. have been found. in practice to this process. In-the first place,"l the vapors passing throughthe scrubber take up and carryover with'them to the condenser, yin mechanical suspension, an excessive amount of -tar;`. and moreover, such excess of tar rendersfthis distillate unsuitable for immediate treatment-with lime *and unsuitable also for rectification, as the tar tends to apparatus.

The object-of my invention is to overcome the above- .objections and to produce 'at a materially reduced cost a pyroligneous acid plug up or clog the rectifying suitable for direct'distillationinzfiihe manufacture of .acetic acid and foriithedirect manufacture of acetate of lime.

To this' end, the invention consists pri-f marily in subjecting the vapors from .the

' carbonizing retort tothe action of reen.

liquor?? (pyroligneous acid) from whic 1 the4 tar has to alarge extent been separated. The manner ofilcarryingout myinvention will be hereinafter described and the disv tinctive featuresA of the invention pointed out in the claims at the end of the specifi cation.' While I have illustrated in the drawing an apparatus well adapted for the practice of my invention, it willbe understood thatthel details of the apparatus may be varied widely by -those skilled in the'art.

The accompanying drawing illustrates 'somewhat diagrammatically the preferred form of the improved apparatus.

'Referring to 'the drawing, A- designates the carbonizing I retort from which the vapors will be conducted by a pipe 2 to the lower portion of a scrubber B. This scrubthedrawing. The liquor within the settling stills or tanks is maintained preferand D2, short branch pipes 8, 9 and lOlead the bottoml of the scrubber B and the pipes i 3 and I(iserve to carry .off vthe tar and the unvapor'ized portionlof the scrubbing liquor respectively from thebottom of the scrubberand from the bottom of the pipe 2'. The

liquor and tar thus delivered to the pump C is forced thence lig/:pipe 7 to the settling stills or tanks D, 'and D2' (in suitable' number), `theso'stills or tanks being heated.v

by steam coilsindicated by'dotted lines in ably at about the boiling point thereof, viz, from 100 to-120 degrees C. From the bottomsl of the settling' stills or tanks D, D-

to a main pipe 11 4that connects with a pump E'from which the settled tar will be forcedby a pipe 12 to a suitable tar recepta'cle (not shown).l Preferably', pipes 5,v 6, 8,.-9 and 10 will be `provided respectively with suitable valves 5t,- 6T,v8a, 9a and 10a.

From the top of the scrubber B -the `vapors are passed tothe top of a condenser F, this condenser being of any familiar or suitable construction,l and from the bottom 90.' of the condenser F leads. a pipe 14, prefer ably-furnished with a-trap l5, to the tank" G,f in which. the green-liquor will be collected. yFrom the bottom of the tank G a pipel will conduct the greenliquor toa neutralizing tank (not shown). Preferably, apipe 17 connected to the pipe 14 leads vto a point beneath the bOcOm of .the retort for taking off the non-condensable gas and supplying it as a part of Ythe fuel whereby the retort is exteriorly heated. From the -bot'- tom-of the tank G, a pipe 2O (preferably formed with a trap 21) and having a valve '22, leads to the top of one of the settling u' .orl green liquor *collectedy in the tank G will pass thence to the several settling stills or tanks D, and D2, so as to maintain a proper supply, of liquor in such tanks at or above the le\ el of the pipes 23 and 24. From the tops of the settling stills or tanks extend respectively'the pipes 25, 26 and 27, these pipes being furnished withvalves 25a,

26a and 27a, and leading to a condenser H that may be of any suitable construction. From the bottom of the condenser H, a pipe 28 leads tothe tank G. The purpose of vthe condenser H is to condense the vapors passing from the tops of the settling stills or tanks D, D and D2. A pipe29 connects the upper portion of the settling still Yor tank D2 With the pump K Aand from this pump .green liquor is forced by the `pipe 30 to the top of the scrubber B Where it will rbe delivered preferably through a suitable spray 31 overthe top of the checkerwork interior of the scrubber.

yand 30a are provided in the pipes 29r and 30.

From the lorgoing description, it will be p seen that my invention is carried out by the apparatus shown, as follows i-As the vapors l from the retort A. are delivered by the pipe 2 -into the bottom of the'scrubber B, they will pass upward through the checker- -work of the scrubberand in so doin will be exposed to the down flowing green iquor delivered to the top of the scrubber.v In thus passing through the scrubber, the tem- .perature of the vapors is very materially reduced as the vapors issue-from theretort at about 650 F. and enter` the condenser 'F at approximately 212 to 250 F. The green liquor delivered at the top of the scrubber passing down through the body lof the scrubber carries with it a large proportion of the tar and condensed products, while the nncondensed vapors pass vto the condenser l Where, being largely' free, from tar, their condensation results in a pyroligneous acid (herein termed green liquor) suitable `for direct distillation in the manufacture of acetic acid, and also well suited for the'direct manufacture of acetate of lime. y

Crude pyroligneous acid consists substantially of Wood spirits 3 to 4; per cent, acetic acid 6` to l0 per cent, dissolved tar 3 to 6 per cent, settled tar l0 to l5 per cent, and the remainder Water. The scrubbing liquor used in the present process is'crude pyroligneous acid or so-called green liquor from which the settled tar has been removed.- lt is passed into the scrubber at about its boiling point, namely, about 100 degrees C., and

` in such copious quanti-ties that, While it Suitable valves 29A neous acid or Green li ucr. lf the li uor in the lower portion ot' the scrubber were largely tarry products, the operation would be subject to much the same defects as previously mentioned when tar or tar oil is employed for scrubbing, namely, the retort gases and vapors would pick up and carry over mechanically a considerable amount Eof the tarry products and tar would accumulate in the scrubberand other parts of the apparatus. y

`Because otits comparatively low boiling point, the pyroligneous .acid scrubbing liquor absorbs a great deal of heat from the retort gases and so effectively condenses the tarry and the tar-forming productsin thc gases.

acid and Water in the'scrubbing liquor and the spirits and acid thus evaporated, as well l as the retort gases, are thereby freed from This action is aided because otthe4 labsorption of heat bythe evaporation of .most of the wood spirits and some-of the tar. The tarry products picked up from the retortfgasesin the scrubber as well as that formed from the ingredients of the pyroligneous acid liquor, are'removed by settling in p the settling tanks and the liquor thus Jfreed from settled tar is again used in the scrubbi-ng'operation. The-losses due to evapo ration in the scrubbing operation and in the settling tanks are made up, as stated, by

green f liquor from the condensing apparatus, so

additions of pyroligneous acid or that-the body of circulating liquor is maintained in the desired volume and also `,is restored to substantially its original composition.-

In practice, it has'been demonstrated,` that the-scrubbing of the vapors with green liquor insures the separation therefrom of a large proportion of the tar and avoids the danger of any accumulation of tar uponthe check` erwork ofthe scrubber or within the con= denser. By arranging the settling stills in series, as

- shown, and as I prefer' todo, a better opportunity-is afforded for the tar to settle before it is pumped olf to the tarreceiving tank.

Inasmuch as the vapors from the retort are g delivered to the bottom of the scrubber at I a very .high temperature, thev heat of these vapors serves to produce Within the scrubber a distilling action which aids in'freeing in great measure the green liquor delivered to the top of the' scrubber from such tar and tarry oils as may be carried thereby and contained therein. This vaporization of ,the green liquor which is being pumped from the settling stills D, D and D? tends to decrease the quantity ot liquor within the settling stills orv tanks, but thisis Icompensated. for. by the supplying of additional green 'liquor to such settling stills or tanks from the tank Gr. The operator in control of the apparatus, by manipulating the valves between the tank G and the settling still or" tank D2, can readily regulate the flow of green liquor from the tank G to the settling stills or tanks, so as to maintain a full supply of such liquor at all times within such tanks. This supply of liquor from the tank G will also serve to replace the tarry prodf ucts that are drawn off from. the bottoms of the settling stills or tanks. It will thus be seen that the process isa continuous one and the pyroligneous acid issuing from' thev tank G is so free' from tar and tarry oils that it is well adapted for use without further distillation in the production of aceticacid or acetate of lime.

It will be understood'that the practice'of' my invention maybe varied as to details-and that features of the invention may be em-V ployed Without its adoption as an entirety. 'Having thus describedv my invention, what I claim as new and desire to secure by Letters Patent is l. The `process of distilling wood which' consists in subjecting the vapors, as -they di"ections-through' a scrubber, withdrawing liquor from the scrubber, and after settling issue from the retort, to the countercurrent A scrubbing action of hot crude pyroligneous acid result-ing from such distillation and from which tar has been settled.

2. The process of distilling wood Which consists in lpassing the vapors from the retort and crude pyroligneous acid in'opposite tar therefrom, returning the liquor to the scrubber..

. 3. The process of' distilling wood which t consists in passing `the vapors from the retort and crude-pyroligneous acid in opposite directions through a scrubber, withdrawing liquor lfrom the scrubber, and after separate ing tar therefrom, returning the liquor to the scrubber, condensing the vapors passing from the scrubber and employing'a portion of the resultant liquor for maintaining a supply of 'scrubbingliquon 4. The process of-distilling wood, which lconsists in scrubbing the vapors from the retort with a circulating body of crude pyroligneous acid, withdrawing tar from the body of scrubbing liquor and adding crude pyroligneous acid thereto to maintain its.

suppl 5. An apparatus lfor distilling wood com prising the combinationof. a carbonizing retort, a scrubber connected -to said retort, a condenser connected to said scrubber, a settling still connectedto the bottom of said scrubber'to receive tar and unvaporized portions of the scrubbing 'liquor from said scrubber, means for conducting a portion of the distillate from the condenser to said ysettling still, means for delivering the liquor from'the upper portion of said settling still tothe top of said scrubber, a supplemental condenser for .condensing the vapors from 4 said settling still, and means for connecting said supplemental lcondenser to the top of said settling still.v

-6 An apparatus for distilling wood comprising the combination of a Carbonizing rctort, a scrubber connected to said retort, a condenser connected to said scrubber, a

series of settling stills connected to the bottom ofsaidvscrubber and adapted to receive Vtar and the unvaporized portion of the scrubbingliquor from said scrubber, means. for'conducting a portion'- of the distillate ,from the condenser to said' settling stills, means for delivering the liquor from the upper portion of said. settlingstills to the top of said scrubber, a supplemental condenser,

.andmeans for connecting said supplemental condenser to the tops of said settling stills.

7. In lthe art 'of .'wood distillation, the process which consistsin scrubbing the hot vapors 'from the retort -with a circulating body of hot, crude pyroligneous acid to thereby remove the'tarry'products and partially'vaporize the scrubbing liquor, condens- .ing thevapors resulting from the scrubbing ,tion of the crude pyroligneous acid in the scrubber and theseparation of tar from the .body Vof. circulating scrubbing liquor in the settling tank, and adding freshA crude pyroligneous acid frointhe condenser to the bodyof circulating scrubbing liquor to main?.

tain its supply. l

9. I- the art of wood distillation, the

8. In Vthe art.. of wood di-stillation,\the4 process which consists in subjecting the hot retort gases and vapors `to the counter-current scrubbing action of crudepyroligneous acid to thereby separate 4tarry products from the .retort vapors and gases, removing the tarry products and unvaporized scrubbing liquor to a settling tank and separately withdrawing the settled tar and the pyroligneous acid liquor employed in the scrubbing operation from the settling tank.

' l0. Inl the art of wood distillation, the process which consistsin passing the hot retort gases and vapors and hot crude pyroligneous acid through a suitable countercurren't apparatus to remove 'tarry products fromA the, retort vapors, withdrawing the il. in the art otwood distillation, themA process which consists in passing the 'hot retort vapors 'and gases and liot crude pyro-V ligneous acid through a' suitable countercurrent scrubbing apparatus to removetarryproducts from the retort vapors, Withdrawing and condensing the vapors from the counter-current apparatus, withdrawing the pyroligneous liquor and the tarry products from the countei'cu1rent apparatus' and, after separating out the tar therefrom, re-- using the liquor inthe counter-current apparatus and maintaining .the supply of scrubbing liquor by adding a portion or the pyroligneous acid produced by condensing 'the vapors. l

12. ln the art ot Wood` distillation, the process which consists in passing thehot retort vapors and gases through ai suitable scrubbing apparatus and then through a suitable condensing apparatus, circulating a body of crude pyroligneous acid continuously and repeatedly through the .scrubbingapparatus and a heated settling tank and thereby 'effecting thereinoval of vtar from the retort vapors in the scrubbing apparatus Y, and the separation of tarl Vfrom4 the'body of. circulating pyroligneous acid inwthe settling tank, and adding fresh pyroligneous acid from the condensing apparatus to the body of circulating scrubbing liquor to maintain its supply.

, 13. Apparatus `tor '1 distilling Wood conr- `prising a carbonizingretort, a scrubber connected thereto, a condenser connected to saidscrubber, a settling tank connected to the r bottom ofthe scrubber tor receiving un.

vaporized scrubbing liquor and tar theremiams from, means for conducting a portion of the removing tarry products from the hot retort' vapors which comprisesrepeatedl'y using a body of crude pyroligneous acid. to eff 4 ecta countercur1ent scrubbing of the hot retort vapors and separately and repeatedly settling andrerncving from the scrubbing liquor the' tarryproducts picked up in theV `scrubbing operations.

' l5. ln Wood distillation, the process of removing tarry products from the hot retort vapors which comprises scrubbing such `vaporsin a counter-current 4othot crude pyroligneous acid, withdrawing the resultant pyroligneous acid liquor and tari-y products and, after settling out vthe tarry products,

using the said liquor for again scrubbing l1ot'retoit'vapois.

16.- ln Woodfdistillation, the process of vremoving tarry products from the hot re-y tort vapors which comprises repeatedly circulating a bodyoi` hot crude pyrol'igneous acid through suitable counter-current scrubbing apparatus and a suitable-settling -apparatus to thereby remove 4tarry products from the hot retort gases in the scrubbing apparatus and separate the tar from said body 'of scrubbing liquor in the settlingv apparatus, and adding freshcrude pyroligneous acid. to the circulatingy body ol? scrubbing liquor to compensate 'for the portion of the liquor evaporatedl in the scrubbingopera tions. y

RALPH il. TWINING. 

